High throughput genotyping assays have allowed the staff of the Laboratory of Genomic Diversity (LGD) to accumulate a large amount of genotypic data on subjects who are members of six large AIDS epidemiology cohorts. The bulk of the genotypes are for diallelic single nucleotide polymorphisms (SNPs) that are within or closely linked to genes that have been nominated as AIDS candidate genes on the basis of what is known about their function. LGD has previously reported significant associations between genotypes for candidate genes and HIV infection susceptibility or progression to AIDS outcomes. The previous work was largely done by analyzing data one SNP and statistical test at a time. In order to efficiently analyze a large amount of accumulating data, a computer program was developed to automate the analysis - AIDS Survival and Categorical Analysis program (ASCA). Written in the SAS programming language, ASCA analyses include: 1) categorical analysis of infection status by genotype, 2) categorical analysis of disease progression by genotype, and 3) survival analysis using the Kaplan-Meier and Cox proportional hazard models. Analyzed disease events include observation of CD4 cell counts of less than 200 per cubic mm, presence of disease meeting the 1993 or 1987 AIDS definitions, cytomegalovirus infection, Pneumocystis carinii pneumonia, Kaposi's sarcoma, lymphoma, mycoplasma infection, and death. The latest version of ASCA can analyze multiple loci in a single run and produces output as PDF format files.